Tire Shredder for Scrap Tyre Size Reduction

Tire shredder for scrap tyre size reduction

A tire shredder reduces whole scrap tyres to 50–150 mm chips using two counter-rotating shafts at 8–15 rpm. BKL supplies the shredding stage on a DS twin-shaft platform. Wire separation, secondary granulation, fibre removal and rubber powder screening are downstream processes needing additional specialty equipment, and we would rather say so at the top of the page than after a quotation.

What follows is what actually changes when you feed tyres into a shredder instead of plastic, and what that means for the machine you buy and the cost of running it.

What makes a tyre different from plastic

Three properties separate a scrap tyre from every other feedstock a shredder normally sees, and each one drives a design decision.

It is elastic. Plastic fractures or shears. Rubber deforms, absorbs the blow and springs back. A blade that would slice through an HDPE drum can push into a tyre wall and simply be pushed out again. Cutting rubber needs a tooth that penetrates and grips rather than an edge that slices.

It is reinforced. Most truck and passenger tyres carry steel belts under the tread and steel bead wire in the rim seat. The machine is not cutting rubber, it is cutting a rubber-and-steel composite — and steel is what destroys tooling.

It is heavy and awkward. A whole truck tyre is a large, rigid, round object that does not fall neatly into a hopper and does not stack. Feeding is a real design problem rather than a detail.

Why low speed is not optional here

The rotors turn at 8–15 rpm. On plastic that speed is a design preference; on tyres it is a requirement, for three reasons that compound each other.

High speed slips. A fast blade skids across elastic rubber instead of biting into it. Slow, high-torque hooks penetrate and pull.

High speed heats. Friction against rubber generates heat quickly, and hot rubber becomes tackier and more elastic — the opposite of what you want in a cutting chamber. Heat also degrades the material you are trying to sell.

High speed cannot survive steel. A steel belt struck at several hundred rpm chips or breaks a blade. Struck at 12 rpm under high torque, it is sheared or the machine stalls — and stalling is recoverable.

That last point is why automatic reverse matters more on tyres than on anything else. The PLC watches motor current; when the load spikes on a bead wire or an undersheared belt, the drive stops, reverses to back the obstruction out of the mesh, then resumes. On tyre work that cycle runs many times a shift, and it is the difference between a machine that keeps running and one that needs an operator with a crowbar.

Steel-belted or not: the decision that drives everything else

Before anything else is specified, establish what proportion of your feedstock carries steel. It changes the tooling, the running cost and the whole downstream plant.

Non-steel tyres — bicycle, motorcycle, some agricultural and solid tyres — are, from the machine’s point of view, tough elastic plastic. Standard alloy tooling handles them and the chips can often go straight to a second reduction stage.

Steel-belted tyres are a different job. Carbide-tipped teeth are the appropriate grade, as in the photograph above, and even those wear against belt wire. Everything after the shredder changes too: you now have steel in your chip stream and a magnetic separation stage becomes mandatory rather than optional.

What comes out

A primary tyre shredder produces rough chips of roughly 50–150 mm, depending on shaft design and on the screen or downstream setup. That is a shred, not a granule.

It is worth being clear about the gap between that and the products people usually have in mind. Tyre-derived fuel takes chips in roughly this range and is the shortest route to a saleable product. Crumb rubber for sports surfaces and moulded goods needs granulation to a few millimetres, plus fibre removal. Fine rubber powder needs finer milling and screening again. Each of those is a separate plant after the shredder, not a setting on it.

Choosing a model by tyre type

Two notes on reading this table honestly.

Quoted capacities are the plastics-duty figures for the DS platform. Tyres are denser and tougher than the mixed plastic these bands were measured on, and a steel-belted feed will sit at the lower end. Treat them as a way to compare models against each other rather than as a guarantee for your material.

“After feeding review” on the DS1600 is not a formality. Truck and engineering tyres are physically large and stiff, and whether one enters the chamber at all depends on rotor diameter against tyre diameter. That is a geometry question we check before quoting, and sometimes the answer is that the tyres need pre-cutting.

Knife wear is the running cost

On a plastics shredder, blades are a maintenance item. On a tyre shredder they are an operating cost, and the single largest variable in the economics after electricity.

Steel belt wire wears tooling far faster than any plastic. Three things follow that should be settled before the machine is quoted, not after:

Blade material against your actual feedstock. Carbide costs more per tooth and lasts longer against steel; alloy grades are cheaper to replace and more forgiving of shock. Which is cheaper per tonne depends on your tyre mix, not on which is the better steel.

Spare tooling on the shelf. A shredder waiting for teeth is a plant that has stopped. Because tooling on this duty is consumed rather than merely worn, spares are a stock item.

Maintenance access. Changing teeth on a machine at floor level with no platform is slow work. The raised-frame arrangement shown above exists for this reason.

Where we stop, and what you still need

BKL covers the rough shredding stage. A complete tyre recycling plant also needs steel separation, secondary granulation, fibre removal and rubber powder screening, and those stages should be planned separately if your target is crumb rubber or rubber powder.

We would rather scope this accurately than sell you a machine that turns out to be one component of a plant you were not budgeting for. If chips are your product, the shredder may be all you need. If crumb rubber is your product, the shredder is the first of four or five capital items.

Is tyre shredding a viable business?

It can be, and the answer turns on five numbers rather than on the machine.

Feedstock supply and gate fees. In many markets you are paid to accept scrap tyres. That gate fee is often a larger revenue line than selling the output, and it is also the one most exposed to local regulation.

Energy. Shredding tyres is energy-intensive per tonne compared with plastic, because you are cutting a composite.

Steel separation. Recovered belt wire has scrap value, but capturing it needs equipment and it will not be clean.

The rubber outlet. Chips into tyre-derived fuel is a low-price, high-volume market with real logistics costs. Crumb rubber sells for considerably more but needs the downstream plant described above.

Tooling and maintenance. Discussed above — and the line most often left out of a first business case.

Buyers who work through those five before ordering tend to be the ones still running three years later. The shredder is one cost centre, not the business.

See the platform machine running

Frequently asked questions